1. Field of the Invention
The present invention relates to the tracking of inventory items including, but not limited to, shipping containers (such as those used in rail and marine terminals), steel coils, steel slabs, concrete slabs, and other such items used in industrial applications. More particularly, the present invention relates to the tracking of inventory in a rail or ship yard using navigation systems and computer software.
2. Description of the Background of the Invention
The tracking of inventory while in transit is critical to many industries, businesses, and organizations. A single freight container may have over a million dollars worth of goods stored therein. If inventory is misplaced, lost, or delivered to the wrong location, it can result in significant lost value and cost expenditure for the shipper. With such significant economic exposure at risk, the tracking of inventory is considered a vital part of the railroad and shipping industry.
Numerous attempts have been made at tracking inventory within a railroad, shipping terminal, or industrial yard. Some of these attempts have used RFID tags, and barcodes. However, these systems may be prone to error if, for instance, dirt or grime obscures the scannable information. Additionally, these systems require RFID tags, and barcode information to be added to each piece of inventory or inventory container. Further, these tracking systems typically do not contemplate tracking the transfer of inventory between vehicles.
U.S. Pat. Nos. 8,055,554 and 7,344,037 (“the Zakula '554 and '037 patents”) disclose a system that tracks a container's location while the container is traveling on a vehicle and when it is put into a storage location. The system disclosed in the Zakula '554 and '037 patents uses GPS, encoders, and latching signal data in conjunction with database information and computer logic to accomplish the task of tracking containers. The system disclosed in the Zakula '554 and '037 patents does not, however, contemplate determining and tracking the transfer of a container from one vehicle to another. There also does not appear to be any disclosure in either of the patents of the use of an inertial navigation system in conjunction with the tracking of the containers.
U.S. Pat. No. 7,916,026 (Johnson) discloses a system that tracks containers and vehicles within a terminal. The system uses specially designed “tags” to accomplish its tracking. The system may also be integrated with GPS. However, the system requires that the tags and/or GPS be mounted on a container in order to track the container.
U.S. Published Patent Application No. 2011/0052001 (Tan et al.) discloses a method for automatically detecting and handling errors in an inventory tracking system. The inventory tracking system uses ID Readers implemented through RFID, bar codes, and/or OCR to detect and ID containers and vehicles. Alternatively, identification data associated with an individual container may be provided by a terminal operating system. However, the Tan et al. publication focuses on error detection, and does not disclose the tracking of container transfers between vehicles. Additionally, while the equipment used in its inventory tracking system is disclosed, the Tan et al. publication does not disclose how its inventory tracking system is implemented.
U.S. Published Patent Application No. 2011/0017693 (Thomas et al.) discloses a system for tracking and locating shipping containers on a rail car in order to enable a gantry crane to locate a particular container more quickly. However, the system requires the use of cameras. Further, the Thomas publication does not contemplate tracking container handling vehicles or tracking container transfers between vehicles.